2 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
3 * are not related to any other subsystem
5 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
7 * This file is release under the GPLv2
11 #include <linux/kobject.h>
12 #include <linux/string.h>
13 #include <linux/sysfs.h>
14 #include <linux/export.h>
15 #include <linux/init.h>
16 #include <linux/kexec.h>
17 #include <linux/profile.h>
18 #include <linux/stat.h>
19 #include <linux/sched.h>
20 #include <linux/capability.h>
22 #define KERNEL_ATTR_RO(_name) \
23 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
25 #define KERNEL_ATTR_RW(_name) \
26 static struct kobj_attribute _name##_attr = \
27 __ATTR(_name, 0644, _name##_show, _name##_store)
29 #if defined(CONFIG_HOTPLUG)
30 /* current uevent sequence number */
31 static ssize_t uevent_seqnum_show(struct kobject *kobj,
32 struct kobj_attribute *attr, char *buf)
34 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
36 KERNEL_ATTR_RO(uevent_seqnum);
38 /* uevent helper program, used during early boot */
39 static ssize_t uevent_helper_show(struct kobject *kobj,
40 struct kobj_attribute *attr, char *buf)
42 return sprintf(buf, "%s\n", uevent_helper);
44 static ssize_t uevent_helper_store(struct kobject *kobj,
45 struct kobj_attribute *attr,
46 const char *buf, size_t count)
48 if (count+1 > UEVENT_HELPER_PATH_LEN)
50 memcpy(uevent_helper, buf, count);
51 uevent_helper[count] = '\0';
52 if (count && uevent_helper[count-1] == '\n')
53 uevent_helper[count-1] = '\0';
56 KERNEL_ATTR_RW(uevent_helper);
59 #ifdef CONFIG_PROFILING
60 static ssize_t profiling_show(struct kobject *kobj,
61 struct kobj_attribute *attr, char *buf)
63 return sprintf(buf, "%d\n", prof_on);
65 static ssize_t profiling_store(struct kobject *kobj,
66 struct kobj_attribute *attr,
67 const char *buf, size_t count)
74 * This eventually calls into get_option() which
75 * has a ton of callers and is not const. It is
76 * easiest to cast it away here.
78 profile_setup((char *)buf);
82 ret = create_proc_profile();
87 KERNEL_ATTR_RW(profiling);
91 static ssize_t kexec_loaded_show(struct kobject *kobj,
92 struct kobj_attribute *attr, char *buf)
94 return sprintf(buf, "%d\n", !!kexec_image);
96 KERNEL_ATTR_RO(kexec_loaded);
98 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
99 struct kobj_attribute *attr, char *buf)
101 return sprintf(buf, "%d\n", !!kexec_crash_image);
103 KERNEL_ATTR_RO(kexec_crash_loaded);
105 static ssize_t kexec_crash_size_show(struct kobject *kobj,
106 struct kobj_attribute *attr, char *buf)
108 return sprintf(buf, "%zu\n", crash_get_memory_size());
110 static ssize_t kexec_crash_size_store(struct kobject *kobj,
111 struct kobj_attribute *attr,
112 const char *buf, size_t count)
117 if (strict_strtoul(buf, 0, &cnt))
120 ret = crash_shrink_memory(cnt);
121 return ret < 0 ? ret : count;
123 KERNEL_ATTR_RW(kexec_crash_size);
125 static ssize_t vmcoreinfo_show(struct kobject *kobj,
126 struct kobj_attribute *attr, char *buf)
128 return sprintf(buf, "%lx %x\n",
129 paddr_vmcoreinfo_note(),
130 (unsigned int)vmcoreinfo_max_size);
132 KERNEL_ATTR_RO(vmcoreinfo);
134 #endif /* CONFIG_KEXEC */
136 /* whether file capabilities are enabled */
137 static ssize_t fscaps_show(struct kobject *kobj,
138 struct kobj_attribute *attr, char *buf)
140 return sprintf(buf, "%d\n", file_caps_enabled);
142 KERNEL_ATTR_RO(fscaps);
145 static ssize_t rcu_expedited_show(struct kobject *kobj,
146 struct kobj_attribute *attr, char *buf)
148 return sprintf(buf, "%d\n", rcu_expedited);
150 static ssize_t rcu_expedited_store(struct kobject *kobj,
151 struct kobj_attribute *attr,
152 const char *buf, size_t count)
154 if (kstrtoint(buf, 0, &rcu_expedited))
159 KERNEL_ATTR_RW(rcu_expedited);
162 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
164 extern const void __start_notes __attribute__((weak));
165 extern const void __stop_notes __attribute__((weak));
166 #define notes_size (&__stop_notes - &__start_notes)
168 static ssize_t notes_read(struct file *filp, struct kobject *kobj,
169 struct bin_attribute *bin_attr,
170 char *buf, loff_t off, size_t count)
172 memcpy(buf, &__start_notes + off, count);
176 static struct bin_attribute notes_attr = {
184 struct kobject *kernel_kobj;
185 EXPORT_SYMBOL_GPL(kernel_kobj);
187 static struct attribute * kernel_attrs[] = {
189 #if defined(CONFIG_HOTPLUG)
190 &uevent_seqnum_attr.attr,
191 &uevent_helper_attr.attr,
193 #ifdef CONFIG_PROFILING
194 &profiling_attr.attr,
197 &kexec_loaded_attr.attr,
198 &kexec_crash_loaded_attr.attr,
199 &kexec_crash_size_attr.attr,
200 &vmcoreinfo_attr.attr,
202 &rcu_expedited_attr.attr,
206 static struct attribute_group kernel_attr_group = {
207 .attrs = kernel_attrs,
210 static int __init ksysfs_init(void)
214 kernel_kobj = kobject_create_and_add("kernel", NULL);
219 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
223 if (notes_size > 0) {
224 notes_attr.size = notes_size;
225 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
233 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
235 kobject_put(kernel_kobj);
240 core_initcall(ksysfs_init);